Tool bit



DEC. 9 G. W. LAPP TOOL BIT Filed Aug. 22, 1919 INVENTOR- WITN ESSEScitizen of the United Patented 1)....9, 1924.

UNITED STATES t ,GROVER w. LAIPP, or LE nor, new YORK.

' TOOL, m;

Application filed August 22, 1919. Serial No. 319,046.

To all w/iom it may concern.

Be it known that I, GnovER lV. LAPP, a States, and a resident of LeRoy,in the county of Genesee and State of New York, have madea new anduseful'Invention in Tool Bits, of which the .following is aspecification.

y invention relates to the forming of the cutting edges orbits ofitoolsby the use of artificially formed crystals of extreme hardness such asare' produced in electric furnaces in the'manufacture of siliconcarbide,

\ during tooledges are'nec'essary'. I have il-' the fused bauxiteor'similar compounds, such as are commerclal-ly known 'as carborundum,cr stolon, alundum, alox1te,etc.

hile my invention has been applied to manufacture of clay products andis particularly adapted'for use in that'industry, it may also be used toadvantage in the rubber and other industries where keen, en-

lustrated my invention inthe form of a tool used in clay turning lathes.

v It has hitherto been customary to use steel tools for machiningarticles of clay after the latter have been molded but before they havebeen fired. The materialsenteringinto the composition of the. claycbodyvary in degrees of hardness from comparatively soft substances up tosuchhard element? as particles of quartz and corundum. The attemptto'machine articles ,of such composition is analogous 'to an effort tomachine a grinding Wheel. Even With the very highest grade of steeltool,there is an immediate dulling which decreases the efiiciency of the tooland necessitates early and frequent regrinding,

resulting in a departure .from the original contour of the tool, rapidconsumption of the steel and serious losses of time due to regrindingand resetting.

The Qb ect of my invention is to provide a cutting edge of bit capableof withstanding the dullmg action of materials such as described above.In the production of the electric furnace products mentioned above,crystals are formed, varying in size and shape but uniform in the highdegree of hardness which has made them ,so valuable when crushed andbonded together in the formof abrasive wheels. of these crystals andutilize them for the cutting-ed es of tools in the manner set forth in te' accompanying-drawings, in

which Figure'l illustrates typical forms in. crystals are produced; Fig.2'is which the of crystals.

I select the larger.

a View of a single crystal after it has been prepared for tool use; Fig.3 is a view of a tool of which a single crystal forms the bit and Fig. 4is a view of a tool which has an extended cutting edge formed by aplurality It should be remembered that an aggregation of small crystalsforming an earthy .mass having a multitude of minute depressions andelevations will be muchdess harder than a/single crystal. 7 I The largercrystals 1 as formed in the electric furnace appear to be of. laminatedp structure and while most ofthe crystal surface is marked with striae 2formed apparently bythe edges of lapped laminae, there are many crystalsone end of which hasa face conslsting of a single lamina 3 having asmooth mirror like surface terminating in edges 4; these edges formingangles of 120 degrees with each other. I utilize such crystals byshaping the surface to the form desired in the finished tool, such as isshown in crystal 5 in Fig. 2. This'may be done. roughly by fracturingthe crystal edge to approximate the desired outline and slowly grindinga, smooth regular contour by the use of abrasive wheels of similarmaterial and preferably shaping may be done .entirely by While it ispossible to use a few of the crystals in their natural state and on someclasses of work without subjecting them to the above preparation, suchtreatment will generally be found desirable, and with some crystals andfor some Work will be necessary.

After it with a tool shank or handle 6. One method of doing this is toinsert the crystal in a mold and pour the molteribabbi'tt, brass orother metal which forms shank 6 into the mold and around-the crystal.The crystal mayl'be attached to the inside of a t 'n wire Or a bit ofclay so tain the position of the crystal in the mold es of the crystal og pp ng y After casting the shank, any. metal interfering with thecutting edge or the escape. of cut material may be ground or cut awavbut the remaining inetal will hold the bit and support it as near thecutting edge as desired' of the finer grains. Or the grinding.

preparing. the crystal 5, I assemble The rough the mold by as to main-Another method of forming the tool'is to shape ashank'from a bar andprovide a' ness and ability to withstand deformation butwvith anaccompanying lack ofhardness. The latter quality, essential for the partof the tool in contact with the work but not elsewhere, is supplied by afragment of one of the hardest of known substances.

The advantages of tools so produced are apparent. They are not onlysuperior to the clay contains much present tools in eneral use ineconomy, du-

bility and e ciency', but are efiective a ainst material whichimmediately dull the e ge of tools of the highest grade of steel orsteel alloys. Where fine steel tools have required grinding and settingfor each unit that was machined, the tools described herein will machinequantities of. the same units shank, a metal nose connected withoutattention.

' Their superiority oven steel tools may be better appreciated when itis realized that feldspar and quartz which are placed at 6 andrespectively in Mohs scale .of hardness'for minerals, and

both of which will readily tool steel. 'Everi 'stellite, a non-ferrousalloy extensivel used for tipping tools is rapidly abrad when usedsilicon carbide crystals are placed at 9.8 on Mohs scratch the best ormachining 35 articles of clay. In contrast thereto,

scale of hardness, approximating the hardness of the diamond, whichranks as 10, but not open to t e objections to the commercial use of thediamond and which, when produced, crystallizes an ideal flat form notexhibited by the diamond.

I claim 1. The combination in a cutting tool of a shank and a siliconcarbide crystal mounted in said shank so as to form a cutting ed e.

2. The combination in a cutting tool 0 a shank and a silicon carbidecrystal mounted in said shank and shaped so as to form a cuttinlg edge.

3. he combination in a cutting tool of a' shank and a silicon carbidecrystal mounted;

in saids'hank, said crystal having a projecting part shaped so as toforma cutting edgeand a.part of irregular contour embedded in said shankand cooperating with the contactin surface thereof to rigidly hold saidcrysta in operative position. 44A cutting tool, comprisingl a metal tereto andv a facing for .the upper face of said nose formed from asilicon carbide crystal and sha ed substantially to the upper face of Asai nose and having its cutting edge re- "inforced by the metal of saidhose so that the forces to which the cutting edge is subjected aretransmitted to the nose.

-In testimon whereof, I have hereunto subscribed my and this 20th day ofAugust, 1919.

GROVER w.'LA1- P.

